628 EDWAHD HULL ON THS CLASSIFICATION 



Stage F. Coal-measures. — Sandstones, clays, and shales, with numerous feet, 

 beds of ironstone and coal. Fish-remains abundant, also Anthra- 

 cosia, Anthracomya, and Anthracoptera. One or two marine bands 

 occur over the " Ten-foot Coal of Hanley"* 3500 



Stage E. Gannister Beds. — Black shales and flags, with a few thin coals 

 and red ironstone. Orthoceras, Goniatites Listeri, Lingula, Aviculo- 

 pecten papyraceus, Anthracomya 1000 



Stage D. Millstone Grit. — Coarse grit, shales, and flags , 1000 



Stage C. Yoredale Beds.— Dark shales and yellow grits, with marine 

 shellst, — Goniatites excavatus (Phil.), G. obtusus (Phil.), G. reticu- 

 lata (Phil.), G. truncatus (Phil.), Macrocheilus, Aviculopecten pa- 

 pyraceus, A. alternatus, Inoceramus, Ctenodonta gibbosa, Myalina, 

 Discina nitida, Productics longispinus, &c 3100 



Stage B. Carboniferous Limestone. 



(Base not visible). 



The very complete lists drawn up by the late Mr. Salter J, prove 

 that the great mass of the central measures were either estuarine or 

 freshwater — the Mollusca being represented by Anthracosia and its 

 congeners, — while those of the Lower Coal-measures are distinctively 

 marine. Mr. Ward, F.G.S., of Longton, however, has discovered 

 two bands of marine shells amongst the Middle Coal-measures. One 

 of these, in the black shale, overlying the " Bay Coal " contains shells 

 of the genera Nautilus, Goniatites, Aviculopecten, Melania, Prochictus, 

 Discina, and Lingula ; and Mr. Ward informs me that he has lately 

 discovered another band with similar fossils above the " Ginmine" 

 coal, near the bottom of the Middle Measures §. 



(4) Flintshire and Denbighshire. 



feet. 

 Stage G. Upper Coal-measures. — Red and grey sandstones, red clays, 

 shales, and a few thin coals. A band of limestone with Spirorbis 

 carbonarius. 1000 



Stage F. [Middle'] Coal-measures. — Sandstones, shales, &c, with coal- 

 seams and ironstones, fish-remains || and Anthracosia, &c 800 



Stage F. Gannister Beds. — Grits, flags, and shales, with thin coals. Go- 

 niatites, Aviculopecten, &c.^[ 1000 



Stage D. Millstone Grit — Massive grit, coarse and fine, with shales 800 



Stage C. — Shales (series thin here) 100 



Stage B. — Carboniferous Limestone 1000 to 1500 



Stage A. — Shales, thin or absent to 30 



* Salter, ' Iron-ores of Great Britain,' part ii. Appendix. Mr. Salter has 

 given very complete lists of the beds in descending order. With two exceptions, 

 the truly marine genera are confined to the Lower Measures. 



t Determined by Mr. Salter and Mr. Etheridge, " Geology of Stockport, &c," 

 Mem. Geol. Survey, 1866. 



\ Loc. supra cit. § Letter, dated Aug. 4, 1876. 



|| Bhizodus, Cozlacanthus, Platysomits, and Palceoniscus, according to Sir P. 

 Egerton. 



^[ Determined by Mr. Binney, F.R.S., and communicated to the writer, ' Coal- 

 fields of Great Britain,' 3rd ed. p. 149. 



